The present invention relates to an apparatus for automatically determining the rate of plasticizer absorption of a powdery resin such as vinyl chloride resins, ABS resins and MBS resins.
When preparing resin powder or forwarding the powdery product from a manufacturing plant, the product is in general subjected to quality inspection for various predetermined physical and/or chemical properties. The results thus obtained are sent back to the manufacturing plant for the improvement of production processes or they are used in the denoration of the quality thereof in order to afford convenience to the destination or the consignee.
In case of, for instance, vinyl chloride resin powder, one of the items for the quality inspection thereof is to inspect the powdery resin for the rate of plasticizer absorption. The term "the rate of plasticizer absorption of a powdery resin" herein means the amount of a plasticizer absorbed by a predetermined amount of resin powder. The rate of plasticizer absorption can in general be determined by weighing out a powdery resin sample, adding an excess &mount of a plasticizer to the weighed powdery resin sample, separating the excess plasticizer from the mixture after the powdery resin sample sufficiently absorbs the plasticizer and again weighing the powdery resin sample to determine the rate of plasticizer absorption of the sample on the basis of the weight gain. The rate of plasticizer absorption of a powdery resin can thus be determined, but there has not yet been developed any apparatus for automatically determining the rate of plasticizer absorption of a powdery resin sample.
Conventionally, the determination of the rate of plasticizer absorption has been carried out manually and accordingly, it requires much labor and time to carry out operations such as the operation for precisely weighing out a powdery resin sample and that for precisely weighing out a plasticizer absorbed. The manner of carrying out these operations slightly varies depending on operators and this is reflected in the measured values. In particular, it takes much labor and time to recover and/or abandon the plasticizer obtained during the separation of the excess plasticizer from a powdery resin sample.